Why is it "wrong" to put Adobe RGB images on websites?

Discussion in 'Digital Darkroom' started by dan_south, Feb 10, 2010.

  1. I shoot in Adobe RGB. When I prepare an image for display on my website I convert it to a JPEG file in the sRGB color space. Why? Because I've always read that sRGB is best for the web.
    However, when I convert the file from Adobe RGB to sRGB, the colors always appear to fade. To counteract this I have to go back into the file and boost contrast, saturation and other parameters and reconvert the file until it looks "about right" in sRGB. (It's never exactly right.) This is a nuisance and a big waste of time and effort. If I convert the file to a JPEG in the Adobe RGB space it looks fine. Is there really a compelling reason NOT to upload the Adobe RGB version of the file to the web?
    Thanks in advance for your responses!
     
  2. Most web browsers don't pay attention to the color space of a photo and assume sRGB. Since Adobe RGB is a wider space then sRGB if you post photos to a website in Adobe RGB the colors are going to look less saturated then look in your editing programs, which does pay attention to the color space.
    What I don’t understand is why the colors are sifting when you convert, if everything is done right in the conversion the colors should look the same, with the possible exception of colors that our outside of the sRGB color gamut but inside your monitor’s gamut. Since most monitors don’t have much outside of the sRGB color gamut I would not expect to see a difference.
     
  3. I think you would benefit a lot (and be able to answer your own question) if you read this webpage (full of example images to see)
    http://regex.info/blog/photo-tech/color-spaces-page1
    When you convert to sRGB, by the way - are you sure you're actually converting the file to sRGB rather than just changing the profile without altering the data? That would certainly wash out the colours.
    As to why you should NOT put the Adobe RGB images on the web - the short answer is because other people's browsers will not display the image correctly. The long answer is in the webpage I listed...
     
  4. However, when I convert the file from Adobe RGB to sRGB, the colors always appear to fade​
    Where?On color managed applictions?
    Most web browsers don't pay attention to the color space of a photo and assume sRGB​
    Non color managed Browser are non color managed : RGB data are sent to graphic card without any transform.
     
  5. However, when I convert the file from Adobe RGB to sRGB, the colors always appear to fade.​
    One possible cause is that there might be a problem with your color space conversion, since correctly converting images from Adobe RGB to sRGB should not change their appearance much as viewed in a color managed application. Is it possible that you are only applying the sRGB profile instead of converting to it? This would cause the colors to fade since the Adobe RGB data is unchanged but no longer marked correctly.
    I recommend against editing the image until it looks “about right” separately for Adobe RGB and sRGB. For many images the two will be completely indistinguishable.
    Could you post two sample images, one Adobe RGB and the other faded in sRGB with no edits?
    The reason not to upload web images in Adobe RGB is that people without color managed web browsers will see the wrong colors, in fact they will see exactly the problem you describe where the colors fade.
     
  6. Dan, maybe your Adobe RGB file are too saturated due to the how you process them at first..? My Adobe RGB vs sRGB look pretty close when i put them side by side in the same software. In general people tend to play many time in a out of gammut area because they like the saturated look of there image, and like what they see on screen.. on a color managed or not (most of the time) display.
    The result is then what they like but not what could be print therefore when they convert (not applied) to a profile like sRGB or CMYK they are always deceive by the result. Maybe you could also just export your raw file after processing to a sRGB color space rigth away and when working in Photoshop you wont have any switch in your workflow, and then save many minutes not redoing your britghness contras and saturation ...
    Why cant you use a adober rgb file with a web browser..just try it and see ; ) Other than Safari and Firefox (to my knowledge) no other web browser are color managed, therefore your image could be seen darker and dull compare to a sRGB.
     
  7. Maybe an example makes things clearer. If you save a pixel in the color red=200, green=0, blue=0 in a file, this color will be interpreted differently depending on the color space. With sRGB it represents a paler red, and with Adobe RGB a much more vivid red. Adobe RGB embraces more vivid colors than sRGB does, and thus can cover more of the available color range, but of course in a coarser way.
    If your file is for the Adobe RGB color space, and the software (like a browser) thinks it is in sRGB, it follows from the above that all colors will become less saturated. A software, which interprets the color spaces saved in the file correctly, is called color managed. Most browsers are not.
    On the other hand, your monitor might not be able to actually display the bright colors. The translation can be thought of as two staged: from RGB in the color space to the correct color, and from there to the monitor. The latter calibration is a different story.
    I attach an image, where I demonstrate the effect of using a wrong color space. In the middle, there are colors from bright red to bright green and all combinations inbetween. Left is the way this file would look like, if it was converted to Adobe RGB, but displayed as sRGB. All colors become less saturated. On the right is the way this file would look like, if AdobeRGB was assigned, i.e., the values are simply interpreted for Adobe RGB. The colors become oversaturated.
    00VkE4-219625684.jpg
     
  8. digitaldog

    digitaldog Andrew Rodney

    If you save a pixel in the color red=200, green=0, blue=0 in a file, this color will be interpreted differently depending on the color space.​
    I’m not sure I’d say the are interpreted as different colors. They are different colors. Numbers alone don’t define color appearance, you also have to define the scale so that it is understood where they lie in relationship to human vision (that big horseshoe shaped plot known as the CIE chromaticity diagram). R0/G255/B0 is not the same color in sRGB as Adobe RGB or Pro Photo RGB or Epson Luster RGB etc. The numbers are the same, the color isn’t because the scale isn’t the same just as a liter of gas isn’t the same as a gallon of gas.
    If your file is for the Adobe RGB color space, and the software (like a browser) thinks it is in sRGB​
    Non ICC aware applications, these browsers included don’t know what sRGB is. This is a language the simply don’t know exists. They take the actual numbers in the document and send them directly to the display. Further, these applications know nothing of the display profile so they can’t use the Display Using Monitor Compensation architecture necessary to provide the correct color appearance (data color space + display profile = preview).
    Since the sRGB color space was designed mathematically to describe a very particular display (a CRT with known phosphors) and even modern LCD’s were designed to mimic somewhat this behavior, sRGB on displays looks OK in non color managed apps but there is no guarantee (and its unlikely) the same sRGB numbers appear the same on any two displays outside ICC aware applications. But they don’t look awful like using color spaces who’s behavior is a mile away from the behavior of the display.
    I attach an image, where I demonstrate the effect of using a wrong color space. In the middle, there are colors from bright red to bright green and all combinations inbetween. Left is the way this file would look like, if it was converted to Adobe RGB, but displayed as sRGB. All colors become less saturated. On the right is the way this file would look like, if AdobeRGB was assigned, i.e., the values are simply interpreted for Adobe RGB. The colors become oversaturated.​
    They look identical to me.
    A better example might be: http://www.color.org/version4html.xalter
     
  9. Dan, I too use Adobe RGB and have the same experience that you have with faded looking colors. I confess that I prefer colors that pop, so my colors may appear a bit too saturated. From the responses here, I'd say the answer is a simple "because..." with a lot of explanation going nowhere. I appreciate all the responses; they just don't translate for me. The most acceptable answer to me is that sRGB offers a standard for all different browsers. I have been criticized for using RGB on the web, so I generally go to the PS edit menu and "assign profile" sRGB to web attachments. This way my colorspace default remains RGB. Thanks for raising the question.
     
  10. Until Dan answers Jacopo's first question we're not getting anywhere here.
    Nothing makes any sense about Dan's initial post because he isn't filling in all the details of his setup and workflow. And I'll even surmise he doesn't fully understand color management in general or else he'ld have already known to include the details needed to answer his question.
     
  11. Dan, I took a look at your website, and see that you have patches of very strong colors showing up a lot of images. I have a hard time believing they could have photographed that way, so I think that Patrick is likely correct about what is going on (oversaturating, etc).
    In other words, you are likely creating colors which simply don't exist in sRGB. So when you convert from Adobe RGB to sRGB, saturation is necessarily lost. It's as though a carpenter saws a board to 14 inches long, but then has to convert it to be measurable with a 12 inch rule (that is, 2 inches get sawed off).
    Here's a specific example from your website: the red doors on the stone building are at the gamut limt for whatever color space, with RGB values of about 145, 0, 22. If these values are in Adobe RGB, then converted to sRGB, you WILL LOSE about 15-20% of the saturation. Again, very much like starting with the 14 inch board, which you like, but on conversion it ends up being sawed down to 12 inches.
     
  12. If you get less saturated colors in sRGB is because you are assiging the profile and not converting to it.
    If you have an image in AdobeRGB that has colors out of the gamut of sRGB what will happen is they will be blown in sRGB. This is because sRGB is a matrix profile and the conversion is always colorimetric even if you select perceptual intent.
    The only sRGB profile which you can convert to with perceptual intent is the version 4 sRGB, you can find it at www.color.org, but then the only browser that will display it correctly is Safari.
    Regarding browsers: Neither IE nor Chrome support color management. Firefox latest version supports only version 2 profiles. Only Safari has full support for color managemet
     
  13. I think Joe and Larry have provided Dan the answer he needs. Joe said:
    Is it possible that you are only applying the sRGB profile instead of converting to it? This would cause the colors to fade since the Adobe RGB data is unchanged but no longer marked correctly.​
    I make sure I 'convert' rather 'assign' when I switch an image to sRGB, and never have the issue that Dan complains of. Larry said:
    I too use Adobe RGB and have the same experience that you have with faded looking colors. .... I generally go to the PS edit menu and "assign profile" sRGB to web attachments.​
    The only way I can replicate Dan's problem is to do what Larry says he does. When I use Edit>Convert to Profile (NOT the Assign Profile option) there are no changes I can see in an image.
     
  14. ...when I convert the file from Adobe RGB to sRGB, the colors always appear to fade.​
    Do the colors fade at the time you convert? Not clear.
    Do they fade when saving in "Save For Web"? Not clear.
    Do they fade only when viewed in a non-color managed web browser? Not clear.
    Does he embed the sRGB profile when saving for the web and view in color managed
    web browser? Not clear.
    Colors fading is the exact opposite of what happens when converting to sRGB and viewing the image on a wide gamut display. Something is really messed up in his workflow just on this fact alone.
     
  15. Dan,
    Why are you not soft proofing in the profile being used or at least soft proof in a non color managed app?
    Seems that would clear this up immedietly.
     
  16. Kevin, it appears to me that Dan is 'soft-proofing' - he is looking at his images on screen once he has applied the sRGB profile and not liking what he sees. I still think the issue is likely to be with how he applies the sRGB profile - is he 'assigning' or 'converting'?
     
  17. >> If you have an image in AdobeRGB that has colors out of the gamut of sRGB what will happen is they will be blown in sRGB <<
    After Francisco's post, I thought I had not been clear what I meant when I said "saturation is necessarily lost." However, I had picked a poor example of a color. The strong red I mentioned, with Adobe RGB = 145, 0, 22, IS indeed on the gamut edge. However, it turns out that it is also exactly on the edge of sRGB gamut and does not get clipped. So when I said it will lose saturation, I clearly made a mistake; the color I picked DOES NOT desaturate on "convert" from Adobe RGB(1998) to sRGB.
    A different red, which DOES desaturate on conversion, is: Adobe RGB = 255, 45, 45, this converts to sRGB = 255, 41, 41, where the "specified color" has lost saturation (roughly 10-15%). To get an idea of the change, one can take the sRGB form and "convert" back to Adobe RGB, now getting 220, 44, 44. To restate this, the starting Adobe RGB = 255, 45, 45, was shifted to Adobe RGB = 220, 44, 44, which is substantially different. The color has essentially lost saturation.
    I should be clear that this loss of saturation clearly occurs in the specification of the color. However, people using monitors limited to sRGB might NOT see a difference, and erroneously conclude there is no change. Going back to my previous analogy of the board, starting at 14 inches, but being clipped to 12 inches - if you were looking at the board through a 12 inch window, you might conclude that no change ocurred. Only the guy with a 14 inch wide-gamut window would realize what happened.
    As a last comment, I'm trying to make explanations that I would have personally wanted to hear 8 or 10 years ago; I'm not sure if anyone here finds any value in this. If so, please make a comment, else... This is even more tedious writing than it is reading!
     
  18. Bill, you are right about losing saturation in the colors that are outside of the sRGB gamut and they cannot be restored if you convert back to AdobeRGB.
    The point I was trying to make is that if you have a color in AdobeRGB which is outside of the sRGB gamut, it will be converted to a clipped or blown out color in the sRGB space. This clipped color in sRGB will be less saturated than the original color in AdobeRGB, there is no question about that. It is just that the original color does not exist in sRGB. In this case, no matter what correction you do you will never get a more saturated color while you stay in sRGB.
    My understanding of the OP is that after going to sRGB the colors appear to fade and some editing has to be performed to get them back. This is what happens when you "Assign" a profile instead of "Convert" to a profile. He will not be able to get the colors back if they were already clipped.
     
  19. >> In this case, no matter what correction you do you will never get a more saturated color while you stay in sRGB. <<
    hmmm...that's a good point, and the OP DID say he made corrective adjustments afterwards.
    My first suspicion, in cases like this, usually is the erroneous "assign" rather than "convert to" profile. But this OP specifically said, "when I convert the file from Adobe RGB to sRGB...".
    But your point that the clipped colors cannot be edited back in, while the smaller color space is in effect, seems a conclusive argument against the situation I proposed. Still, I'm not really confident that the mystery has been solved. But only the OP can confirm that, I think.
     
  20. > most viewers won't see the colors you intend. They'll be on Explorer...

    Wrong, Internet Explorer is now used by < 50% of users. [statowl.com] Color managed browsers are approaching 50% and are probably already above that level for image-conscious viewers.

    In my opinion shooting AdobeRGB is just stupid. The only reason do to this is if your workflow is limited to 8 bits per color and you are producing images for offset printing. If you are producing CMYK images for offset printing, you should have converted to 16 bit workflow and ProPhotoRGB. If you are producing just web images, sRGB is more than sufficient.

    Nice example, Rene GM! Very useful.
     
  21. The only reason do to this is if your workflow is limited to 8 bits per color and you are producing images for offset printing...
    If you are producing CMYK images for offset printing, you should have converted to 16 bit workflow and ProPhotoRGB....

    Not sure i follow you there Bill?.. did you mean;
    "If you are NOT producing CMYK images for offset printing, you should have converted to 16 bit workflow and ProPhotoRGB" i hope so ; )
    But still, i dont think it is necesary for most user to have a Pro Photo worklfow, neither a 16bit. Common user that dont do landscape shot with a lot of gradient or high end portrait for cosmetic campaing dont need Pro Photo or a 16bits workflow.. certainly not if they do not fully understand color management to start with anyway.
     
  22. digitaldog

    digitaldog Andrew Rodney

    i dont think it is necesary for most user to have a Pro Photo worklfow, neither a 16bit.​
    The read this and get back to us:
    The Role of working spaces in Adobe applicaitons
    http://www.digitalphotopro.com/gear/imaging-tech/the-bit-depth-decision.html
     
  23. Always the same song:
    1- ProPhoto is the best
    2- 16 bit is a must
    Do you know that ProPhoto is difficult to use, as no display or printer can show such huge gamut?
    Do you know what happen increasing saturation on Prophoto?
    From the second link:
    Most modern capture devices, such as digital cameras and scanners, collect more than 8-bits per color channel. The manufacturers of these devices do this for a reason. The vast majority of digital cameras can produce 12-bits per channel, while some can capture 14-bits, and a rare few can capture 16-bits per channel.

    What's important here is that these devices provide a finer degree of numeric values between pure white and pure black per color channel. A 12-bit file can define 4,096 steps from black to white, a far cry from the 256 steps in an 8-bit file.​
    But they omit (but I suppose they don't know) that 12 bit are linear and 8 bit are compressed.
    Then "gradients" with strong curve adjustement to get posterization.
    Are you a graphic or a photographer?
    Do you edit and print graphics or photos?
    Do you know the effect of noise?
    Please say that ProPhoto have avantages and disadvantages.
    And, please, stop to compare linear encoding vs. gamma encoding.
     
  24. Thanks Andrew for the link, i agrre with all you write in there.. but the fact is that i still think that most of the user in here at least, common user that dont do what whe call high end printing, or heavy retouching or image manipulation dont need 16bits for there christmas party shot or there wedding shot.. and they for sure dont need them in a wide color space if they print at home or in a lab..
    Mathematicaly you are right, but visually, for all the image i can see everyday when i give my workshop or receive by email asking for info.. none of them would be better or worst with a 16bit ProPhoto... Sure, some might say that since you have acces to such info why dotn use it, but the fact is that most of the user dont really understand color management, dont have a calibrated monitor and dont know or understand why the use of sRGB, Adobe RGB so bringing them even further form screen to print with Pro Photo wont help them.
    Better use a simple system that simply work like sRGB and 8bit to start in your digital journey, and work your way up in need than trying to get things going with a system you dont understand at all, but follow blindly because you read it on the web from a reputable source ; )
    If you append to come in Montreal again, let me know it will be my pleasure to meet you and have a coffee with you and talk about simple stuff in life ; )
     
  25. digitaldog

    digitaldog Andrew Rodney

    Do you know that ProPhoto is difficult to use, as no display or printer can show such huge gamut?
    Do you know what happen increasing saturation on Prophoto?​
    Gamut mismatch (fitting round pegs in square holes) It IS true that the wider the granularity in a color space, the harder it is to handle subtle colors. This is why wide gamut displays that can't revert to sRGB (current LCD technology doesn't allow this.) are not ideal for all work (ideally you need two units). There are way, way more colors that can be defined in something like ProPhoto RGB than you could possibly output, true. But we have to live with a disconnect between the simple shapes of RGB working space and the vastly more complex shapes of output color spaces to the point we're trying to fit round pegs in square holes. To do this, you need a much larger square hole. Simple matrix profiles of RGB working spaces when plotted 3 dimensionally illustrate that they reach their maximum saturation at high luminance levels. The opposite is seen with print (output) color spaces. Printers produce color by adding ink or some colorant, working space profiles are based on building more saturation by adding more light due to the differences in subtractive and additive color models. To counter this, you need a really big RGB working space like ProPhoto RGB again due to the simple size and to fit the round peg in the bigger square hole. Their shapes are simple and predictable. Then there is the issue of very dark colors of intense saturation which do occur in nature and we can capture with many devices. Many of these colors fall outside Adobe RGB (1998) and when you encode into such a space, you clip the colors to the degree that smooth gradations become solid blobs in print, again due to the dissimilar shapes and differences in how the two spaces relate to luminance.
     
  26. Simple matrix profiles of RGB working spaces when plotted 3 dimensionally illustrate that they reach their maximum saturation at high luminance levels.​
    What do mean for "luminance"?
    Luminance is Y of CIE_XYZ or Y of CIE_xyY .
    For example:
    -start from R=200,G=200,B=200 in Prophoto
    -compute CIE_LCH (C=Chroma or Saturation)
    L=84.265563, C=0.000184, H=344.601696
    -compute xyY
    x=0.345669, y=0.358496, Y=64.577500
    Now increase C (C=20) without changing L and H, you get:
    x=0.366039, y=0.333029, Y=64.577500
    R=219, G=192, B=210 (rounded)
    As you can see luminance doesn't change if you modify Chroma, of course.
     
  27. digitaldog

    digitaldog Andrew Rodney

    What do mean for "luminance"?​
    Simple, the L*axis when viewed plotting such profiles next to LUT based, output profiles. Easy to do in ColorThink or a similar app.
     
  28. I see, L* is lightness.
    But again, Chroma (Saturation) doesn't change if you modify L*.
    Starting from Lab model, Chroma is = SquareRoot(a*a+b*b), that is the euclidean distance in (a,b) plane from L axis.
     
  29. jacopo,
    Euclidean calculation can't work perfectly when the PCS is Lab which isn't a perfect color model. It has some non-uniformity in certain areas. IOW I imagine there's fudging going on in calculating a lot of this. But then the natural human visual response characteristics primarily influenced by adaptation can introduce its own non-uniformity making a level of precision you're trying to calculate for pretty much unattainable if not unuseable.
    There was a discussion a while back here on a particular Samsung LCD that claimed it had a larger gamut than AdobeRGB after calibration upon examining its 3D model. When I got a hold of this newly made profile and assigned it to an AdobeRGB image, it didn't produce colors that suggested it was all that large of a gamut. Orangey tan brown shadows in skin tone became a maroon rust color while the pinkish peach highlights took on a sickly dull yellow instead of the usual over saturated appearance often achieved assigning AdobeRGB or ProPhotoRGB to an sRGB image. Some of this could've been caused by the Samsung software.
    I can only conclude that all of this color matching stuff with regards to math is primarily about getting a reasonable simulation. But I still have to wonder what others are seeing on their calibrated wide gamut displays of images I've edited on my calibrated sRGB-ish display. From the comments I get on the appearance of color in my images I post here, I'm pretty close and that's all I can expect.
     
  30. Euclidean calculation can't work perfectly when the PCS is Lab which isn't a perfect color model​
    Tim, I know Lab is not perfectly uniform, but it is nearly uniform. I was speaking of saturation on editing software.
    Well there are 2 ways to change saturation:
    1- using HSV/HSL color model derived from RGB
    2- using LCH derived from Lab, derived from XYZ
    There is some nonlinearity in Lab, essentially at low saturation values, but method 2 is the best method to use.
    The role of Lab as PCS has different motivations.
    It's not required that PCS is perceptually uniform, XYZ is as good PCS.
    Let me explain:
    A profile have to encode a color space, but we are interested in transforming images from a color space to a different one.
    A profile, call it ProfileA and call the associated colorspace ColorSpaceA , have to be good to go to ColorSpaceB,ColorSpaceC.........and so on.
    Any ColorSpaceM==>ColorSpaceN transform have to be possible.
    The only way to realyze that is using a Connection ColorSpace (PCS):
    -ProfileA contains info for ColorSpaceA=>PCS and back
    -ProfileB contains info for PCS=>ColorSpaceB and back
    In this way ProfileA and ProfileB can be used to go from ColorSpaceA to ColorSpaceB:
    ColorSpaceA=>PCS=>ColorSpaceB.
    The first transform is from ProfileA, the second transform is from ProfileB.
    Now, how can we chose the PCS ?
    We can choose PCS=XYZ, as CIE synthetized XYZ as human visual gamut. All colors are inside XYZ space.
    It is required that PCS is perceptually uniform?
    No, it is only a common space to go from a color space to a different color space. Indeed XYZ is not uniform.
    There is another thing that must be chosed: the white point.
    Any RGB color space (sRGB,Adobe 1998,ProPhoto,......) is builded fixing primaries (Red,Green,Blue), White and a compression/expansion curve (gamma).
    So when you go from RGB to XYZ the selected White Point enters in the conversion,for example:
    -for sRGB,Adobe 1998 you get XYZ_D65
    -for ProPhoto you get XYZ_D50
    ICC fixed D50 as whitepoint.
    Now the role of Lab as PCS.
    As XYZ have to be characterized from a white point, we know that Lab can be builded from XYZ if you fix a reference White.
    So Lab and XYZ are both good for PCS, and ICC make them both acceptable.
     
  31. Tim,
    for the Samsung profile, it's difficult to say anything.
    But in my experience is not simple to get a "correct" profile, specially on wide gamut display.
    I know there are wonderful monitors (generally expensive) with calibration kit, and there are monitors that are difficult to calibrate and profile.
    Makers are searching to improve hardware and software solutions.
    We hope in the future.
     
  32. digitaldog

    digitaldog Andrew Rodney

    I'm in Quito Ecudor for the week with sporadic email so when I return and have access to ColorThink I'll provide a screen capture. But you're making this more complex than it has to be.
    Printers produce color by adding ink, working space profiles which are theoritically based on emissive devices are based on building more saturation by adding more light. These are due to the differences in subtractive and additive color models. There's the question of clipping. It's not at all hard to capture colors that are outside Adobe RGB. If you convert to this or a smaller space from a capture device that exceeds this gamut, gradations of those colors get clipped to solid blobs in these dark areas of color space. So the advantage of ProPhoto isn't only about retaining all those out-of-gamut colors it's also about maintaining the distinctions between them, so that you can map them into printable space as gradations rather than blobs.
     
  33. So the advantage of ProPhoto isn't only about retaining all those out-of-gamut colors it's also about maintaining the distinctions between them, so that you can map them into printable space as gradations rather than blobs.​
    It is not so simple.
    Gradations are saved if you are inside output gamut.
    When people increase saturation on ProPhoto image, the colors go quickly out of any output gamut (on ProPhoto you can reach values that are not colors too).
    They don't know as monitor can't show the true colors.
    So, gradations are lost.
    Worse, gamut mapping (perceptual intent) is penalized from such very saturated colors.
    You have to be a true expert to use ProPhoto and you need smart hardware and software solutions.
     
  34. digitaldog

    digitaldog Andrew Rodney

    Worse, gamut mapping (perceptual intent) is penalized from such very saturated colors.​
    There is no perceptual table in the ProPhoto working space (matrix profiles don't have them). There are such options going from ProPhoto to an output space, but the that conversion has zero idea of the source space (it gets feed Lab).
    You have to be a true expert to use ProPhoto and you need smart hardware and software solutions.​
    Based on nearly a decade of use by myself and many other users, and the fact that ProPhoto primaries are used in every Adobe raw conversion engine, you'll forgive me if I say this is nonsense. I'm off in a few minutes from Quito to the Galapagos islands to shoot for a week (raw, in ProPhoto <g>), with no net access so, I'm not ignoring the topic, I'm not able to.
     
  35. There is no perceptual table in the ProPhoto working space (matrix profiles don't have them).​
    The perceptual intent is in printer profile (or may be monitor profile, if it is provided).
    Based on nearly a decade of use by myself and many other users, and the fact that ProPhoto primaries are used....​
    I don't understand what are you saying.What do you think is nonsense?
     
  36. if you don't believe me, you can believe ICC:
    ROMM RGB is the best choice for high-end printing on large gamut media, but only experts should use it​
     
  37. Dan,
    Read this, it is an excellent article on how important the rendering intent is , why and what can go wrong, and explains why you are getting colour shifts. These choices can't be laid down, they are best looked at on an image by image basis depending on the colours and the extent of the gamut that is used in the file.
    It is not about how much smaller sRGB is from Adobe RGB, obviously the colours can be replicated because after you readjust you get them where you want them, it is about how the colours are converted to their new space, the different ways this issue is worked out is what you need to work out for your images.
     
  38. Patrick, I mean that sRGB is good enough for most of us who do not produce images for CMYK printing, which is what you are saying as well. ProPhotoRGB and 16-bit RAW conversions require a lot of processing power, which my old computer does not have. For an example of 8-bit AdobeRGB not being sufficient for landscape work, see this thread. I may have done better with my $260 P&S!
     
  39. digitaldog

    digitaldog Andrew Rodney

    ROMM RGB is the best choice for high-end printing on large gamut media, but only experts should use it​
    Indeed, people who don’t have a clue about color management shouldn’t use ProPhoto RGB. Those that understand color spaces and RTFM, use products properly, no issues. I don’t know if that makes the later group experts or those that understand the proper use of the tools.
     

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